In order to diagnose the nutritional disorders caused by various environmental stress, biochemical test, xylem sap analysis and colorimetric petiole analysis were used to assay symptoms well before the severe development. Among the various enzymatic analysis, alkaline phosphatase activity was highly specific to calcium deficiency while in vivo nitrate reductase activity was not stable parameter in response to nitrogen deficiency. Determination of nitrogen, phosphorus and magnesium by colorimetric petiole analysis was sensitive to induced deficiencies. The status of potassium in the plant, however, could be better determined with the xylem sap analysis. Salinity stress induced by low osmotic potential of the nutrient solution increased the activity of alkaline phosphatase, showing similar results as calcium deficiency. Magnesium and phosphorous contents by the colorimetric petiole analysis were particularly low when the roots in anoxia.
Nickel (Ni) is an essential nutrient element for higher plants; although, it has generally been ignored. This is because it appeared that Ni deficiency would not likely occur in field situations. This conclusion is because a) Ni content of nearly all soils is thought to be high enough to satisfy plant requirements, and b) plant Ni requirements were thought to be very low. Thus, plant Ni nutriton has been generally ignored. We report here: 1) the discovery of acute Ni deficiency in field plantings of pecan (Carya illinoinensis); 2) the wide variety of symptoms associated with Ni deficient; 3) soil management conditions that cause Ni deficiency; and 4) potential impact of Ni deficiency on management strategies for crops. Observations indicate that Ni deficiencies are occuring on many woody crops in orchard or nursery situations. Evidence indicates that Ni deficiency is likely a factor in many complex disorders of unknown cause affecting a variety of crops. Ni deficiency problems are likely to become increasing common and severe as a result of contemporary management practices. The information presented identifies a need for greater attention to plant Ni nutrition by practitioners of crop husbandry.
Zinc deficiency is a nutrient disorder that is observed in pecan production areas. In the field it is characterized by a rosette shoot habit and interveinal leaf chlorosis. Up to now, the induction of zinc deficiency has not been accomplishable in the field or greenhouse. Thus any critical evaluations of effects of zinc nutrition on tree growth and development have been lacking. A hydroponic culture system was developed where zinc deficiency was induced. Seedstocks collected from `Stuart', `Curtis', and `Wichita' trees were grown with and without zinc supply. Biomass, leaf area, node number, and visual symptoms were assessed. Foliar deficiency symptoms were rated 4 and structural evaluations were conducted using light and electron microscopy. Significant differences in visual symptoms were observed between treatments and among cultivars. Leaf area significantly decreased in `Stuart' and `Curtis' under zinc deficient conditions. Zinc had no significant effect on biomass and internodal length. Foliar nutrient contents were compared between cultivars. Our data suggest that genotypic differences in sensitivity to zinc deficiency exists and improving pecan production through genetic selection for zinc efficiency appears promising.
Abstract
A series of experiments was conducted with chrysanthemum cv. Giant Betsy Ross grown in acid-washed quartz sand. The nutrient solution was buffered at pH 7.8 to induce Cu deficiency while Fe, Mn and Zn were supplied in high quantities to avoid simultaneous deficiencies. Nutrient levels in the tissues were monitered by atomic absorption analyses.
The critical range of Cu was established at 6.7 to 7.4 ppm for the first fully expanded leaves of the plant. The deficiency first appeared on the terminal leaves as chlorosis most intensely developed at the leaf blade base. As the leaf became more chlorotic the margin, and particularly the lobes toward the leaf apex, retained a normal green color. Tissues over and adjacent to the vascular tissue did not become as chlorotic as the leaf lamella giving rise to the second symptom which was interveinal chlorosis. At that stage the green pigmentation associated with the vascular tissue occurred in a broader pattern than in Fe deficiency. In the third stage of deficiency veinal chlorosis appeared, followed by necrosis of leaves located immediately below the first fully expanded leaf. There was a concomitant regreening of foliage at the terminal end of the shoot which lasted for a short time. In the final stage the shoot apex died.
Abstract
The Diagnostic Recommendation and Integrated System (DRIS) approach was used to identify mineral deficiencies associated with mango decline (a disorder of unknown etiology) of ‘Tommy Atkins’ mango (Mangifera indica L.) trees in the field. Nutrient deficiencies associated with decline were related to the nutrition of entire orchards and not to the nutrient status of individual trees within an orchard. The nutrient imbalance index (NII) was higher for trees in the orchards with the largest percentage of declined trees compared with the healthy orchard. The most deficient elements in orchards with declining trees according to DRIS were Mn, Fe, or a combination of both elements. The concentration of these elements was below the critical value in two of the three declined orchards sampled. Magnesium concentration was generally higher in declined orchards than in healthy orchards. Phosphorus had the most negative DRIS index, but the concentration was still above the critical value in an orchard that contained no declined trees. DRIS determinations from potted trees showing no mineral deficiency symptoms in a previous study also showed P to have the most negative DRIS index. DRIS, when used along with sufficiency ranges, appears to be a useful approach for identifying nutritional deficiencies involved in a mango decline.
Abstract
Seedlings of ‘Babygold 5’ peach [Prunus persica (L.) Batsch] were grown for 50 days in nutrient solutions with 0.4, 21, 42, 125, 250, 500 μm Mg. Magnesium deficiency symptoms were observed 19 days after initiation of the Mg treatments in the seedlings in 0.4 μm Mg solutions. The relative growth rate was significantly increased for the first increment of Mg concentration with no further increases at higher Mg concentrations. Increasing Mg in the nutrient solution significantly increased Mg concentration in the leaves, stems, and roots, but Mg tissue concentration decreased at all levels of Mg in the nutrient solution as physiological age increased. Visible Mg deficiency symptoms were observed on mature leaves at the 125 μm Mg treatment, but when the Mg concentration exceeded 250 μm, Mg concentration in mature leaves was increased above the threshold for appearance of Mg deficiency symptoms. No Mg deficiencies were observed on ‘Babygold 5’ seedlings when the Mg concentrations in the leaves exceeded 2000 μg/g dry weight and Mg uptake rate was 2.5 μmoles/g fresh wt./day.
In class demonstrations, it is almost impossible to maintain the same water: air ratio in growing media. If some treatments result in greater plant growth than others, treatment effects on plant growth are often confounded with the effect of water: air ratio in the growing media. In a laboratory demonstration of nutrient deficiencies symptoms in plants, a controlled water table irrigation system maintained a constant water: air ratio in the growing media regardless of the nutrient deficiency affect on plant growth. The modified capillary mat irrigation system consists of one mat edge extending over the edge of the bench into a narrow trough on the side of the bench. The nutrient solution level in the trough is controlled by a liquid level controller, so it is at a fixed distance below the bench surface. The nutrient solution is drawn upward by capillarity to the bench surface and then moves by capillarity over the bench. The system automatically maintains a constant air: water ratio in the growing media. A standard Hogland solution was modified to demonstrate deficiencies in N, P, K, Mg, Ca, Cu, Fe, and Zn on corn, squash, radish, soybeans, and marigold. Seeds were germinated and grown to maturity in either a 10- or 15-cm pot. Students set up the demonstration, were provided instruction in preparing solutions, regularly observed plant growth, and answered questions at the end of the study about differences in plant growth observed. However, possibly because low concentrations of some minor elements in the capillary mat, Zn deficiency was not observed and other elements, although resulting in poor growth compared to the control, did not show severe deficiency symptoms.
Abstract
Ethylene evolution was determined for tomato (Lycopersicon esculentum Mill.) plants grown under nutrient-deficient (N, P, K, Ca, Mg, S) conditions or under full nutrition with NH4
+ or NO
Abstract
The new mechanical-harvest varieties of tomatoes ‘VF-145’ and ‘VF-13L’ exhibited symptoms of K deficiency under both greenhouse and field conditions, while the older hand-harvested varieties remained free of symptoms. In the field the K-deficient varieties showed deficiency symptoms regardless of the amount of K applied to the soil. In late season the K concentrations in the petioles of the K-deficient varieties were much lower than in the other varieties. There were no differences between varieties in the rate or amount of K absorption from nutrient solutions. Root grafts indicated that there were no differences in the ability of the different rootstocks to absorb K.
Interveinal chlorosis has been observed on the oldest leaves of several varieties of flowering crabapple (Malus sargentii Rehl). Our objective was to identify the cause of this disorder. Foliage and soil from 20 Sargent crabapple trees growing on 12 different sites were analyzed for possible nutrient deficiencies or excesses. Analyses showed N to be slightly low, Ca high, and Mg low in all leaf samples. Soil analysis showed Ca to be abnormally high at all sites. We concluded that the leaf discoloration was caused by a Mg deficiency due to Ca suppression of the Mg and that the low foliar N might be a contributing factor in the interveinal chlorosis.